EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11) 1 RISK ASSESSMENT COVERING PAGE - ABOUT THE PROCESS It is important that policy decisions and action within Great Britain are underpinned by evidence. At the same time it is not always possible to have complete scientific certainty before taking action. To determine the evidence base and manage uncertainty a process of risk analysis is used. Risk analysis comprises three component parts: risk assessment (determining the severity and likelihood of a hazard occurring); risk management (the practicalities of reducing the risk); and risk communication (interpreting the results of the analysis and explaining them clearly). This tool relates to risk assessment only. The Non-native Species Secretariat manages the risk analysis process on behalf of the GB Programme Board for Non-native Species. During this process risk assessments are: Commissioned using a consistent template to ensure the full range of issues is addressed and maintain comparable quality of risk and confidence scoring supported by appropriate evidence. Drafted by an independent expert in the species and peer reviewed by a different expert. Approved by the NNRAP (an independent risk analysis panel) only when they are satisfied the assessment is fit-for-purpose. Approved by the GB Programme Board for Non-native Species. Placed on the GB Non-native Species Secretariat (NNSS) website for a three month period of public comment. Finalised by the risk assessor to the satisfaction of the NNRAP and GB Programme Board if necessary. Common misconceptions about risk assessments The risk assessments: Consider only the risks (i.e. the chance and severity of a hazard occurring) posed by a species. They do not consider the practicalities, impacts or other issues relating to the management of the species. They also only consider only the negative impacts of the species, they do not consider any positive effects. They therefore cannot on their own be used to determine what, if any, management response should be undertaken. Are advisory and therefore part of the suite of information on which policy decisions are based. Are not final and absolute. They are an assessment based on the evidence available at that time. Substantive new scientific evidence may prompt a re-evaluation of the risks and/or a change of policy. Period for comment Once placed on the NNSS website, risk assessments are open for stakeholders to provide comment on the scientific evidence which underpins them for three months. Relevant comments are collated by the NNSS and sent to the risk assessor for them to consider and, if necessary, amend the risk assessment. Where significant comments are received the NNRAP will determine whether the final risk assessment suitably takes into account the comments provided. To find out more: published risk assessments and more information can be found at https://secure.fera.defra.gov.uk/nonnativespecies/index.cfm?sectionid=22
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EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
1
RISK ASSESSMENT COVERING PAGE - ABOUT THE PROCESS It is important that policy decisions and action within Great Britain are underpinned by evidence. At the same time it is not always possible to have complete
scientific certainty before taking action. To determine the evidence base and manage uncertainty a process of risk analysis is used.
Risk analysis comprises three component parts: risk assessment (determining the severity and likelihood of a hazard occurring); risk management (the practicalities of
reducing the risk); and risk communication (interpreting the results of the analysis and explaining them clearly). This tool relates to risk assessment only. The Non-native
Species Secretariat manages the risk analysis process on behalf of the GB Programme Board for Non-native Species. During this process risk assessments are:
Commissioned using a consistent template to ensure the full range of issues is addressed and maintain comparable quality of risk and confidence scoring supported
by appropriate evidence.
Drafted by an independent expert in the species and peer reviewed by a different expert.
Approved by the NNRAP (an independent risk analysis panel) only when they are satisfied the assessment is fit-for-purpose.
Approved by the GB Programme Board for Non-native Species.
Placed on the GB Non-native Species Secretariat (NNSS) website for a three month period of public comment.
Finalised by the risk assessor to the satisfaction of the NNRAP and GB Programme Board if necessary.
Common misconceptions about risk assessments
The risk assessments:
Consider only the risks (i.e. the chance and severity of a hazard occurring) posed by a species. They do not consider the practicalities, impacts or other issues
relating to the management of the species. They also only consider only the negative impacts of the species, they do not consider any positive effects. They
therefore cannot on their own be used to determine what, if any, management response should be undertaken.
Are advisory and therefore part of the suite of information on which policy decisions are based.
Are not final and absolute. They are an assessment based on the evidence available at that time. Substantive new scientific evidence may prompt a re-evaluation of
the risks and/or a change of policy.
Period for comment
Once placed on the NNSS website, risk assessments are open for stakeholders to provide comment on the scientific evidence which underpins them for three months.
Relevant comments are collated by the NNSS and sent to the risk assessor for them to consider and, if necessary, amend the risk assessment. Where significant comments are
received the NNRAP will determine whether the final risk assessment suitably takes into account the comments provided.
To find out more: published risk assessments and more information can be found at https://secure.fera.defra.gov.uk/nonnativespecies/index.cfm?sectionid=22
EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
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GB NON-NATIVE ORGANISM RISK ASSESSMENT SCHEME
Name of organism: Callosciurus erythraeus
Author: Maria Vittoria Mazzamuto, Lucas Wauters, Adriano Martinoli, Sandro Bertolino
Risk Assessment Area: European Union (28 Countries)
Draft: 05/12/2014
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EU CHAPPEAU
QUESTION RESPONSE
1. In how many EU member states has this species been recorded? List
them.
France, The Netherlands, Belgium, Italy
2. In how many EU member states has this species currently
established populations? List them.
France, The Netherlands, Belgium, Italy
3. In how many EU member states has this species shown signs of
invasiveness? List them.
France, The Netherlands, Belgium, Italy
4. In which EU Biogeographic areas could this species establish?
Continental area, probably Mediterranean area
5. In how many EU Member States could this species establish in the
future [given current climate] (including those where it is already
established)? List them.
The species is established in Italy, France, Belgium, The Netherland. It probably
also adapt to climatic condition present in Austria, Croatia, Czech Republic,
Germany, Hungary, Luxembourg, Malta, Poland, Romania, Slovakia, Slovenia,
Spain,.
6. In how many EU member states could this species become invasive
in the future [given current climate] (where it is not already
established)?
The species could become invasive in most of Europe, if established, mainly for the
possibility to reduce population size or even replace the native red squirrel that is the
only native tree squirrel present in Europe. The confidence of this prediction is
higher in parts of Europe where mixed broadleaves forests are dominant and lower
for areas where conifers are dominant.
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SECTION A – Organism Information and Screening
Stage 1. Organism Information
RESPONSE
[chose one entry, delete all others]
COMMENT
1. Identify the organism. Is it clearly a single
taxonomic entity and can it be adequately
distinguished from other entities of the same rank?
Callosciurus erythraeus Pallas, 1779.
EN: Pallas’s squirrel (red-bellied tree squirrel);
FR: ecureuil à ventre rouge (ecureuil de Pallas,
ecureuil de Formose); IT: scoiattolo di Pallas; DE:
Pallas-hörnchen
Yes, this species can be adequately distinguished
from other entities of the same rank
2. If not a single taxonomic entity, can it be
redefined? (if necessary use the response box to
re-define the organism and carry on)
NA
3. Does a relevant earlier risk assessment exist?
(give details of any previous risk assessment)
No A Risk Assessment has been conducted in
Belgium and The Netherlands and the result was
that the species has high potential of establishment
and dispersal in those countries.
4. If there is an earlier risk assessment is it still
entirely valid, or only partly valid?
No They only consider single countries.
5. Where is the organism native?
South East Asia
6. What is the global distribution of the organism
(excluding Europe)?
The species is native to the north-eastern part of
South Asia: it is widely distributed in central and
southern China (Smith & Xie 2008), and mainland
Southeast Asia (Duckworth et al. 2008a). The
countries concerned are: Bangladesh, north-eastern
India (Molur et al. 2005), Myanmar, northern
Thailand, Laos, southern and northern Vietnam,
eastern Cambodia, Peninsular Malaysia and
Taiwan (Moore & Tate 1965, Wilson & Reeder
2005, Duckworth et al. 2008a, Bertolino & Lurz
2013).
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Pallas’s squirrels have been introduced to five
localities of Argentina (Guichón et al. 2005,
Benitez et al. 2010, Bertolino & Lurz 2013) and in
at least 13 areas in Japan (1 area eradicated) (Abe
et al. 2005, Ikeda et al. 2011), and to Hong Kong
(2 known populations) (Ho 1994, Chung & Corlett
2006).
7. What is the distribution of the organism in
Europe?
Southern France (Gurnell & Wauters 1998; Duff &
Lawson 2004; Chapuis et al. 2011), a small area in
south-east of The Netherlands close to Belgium
border (Dijkstra et al. 2009) and north of Italy
(Bertolino & Lurz 2013). In Belgium one of the
two populations of the species has been eradicated
(Stuyck et al. 2009) while a limited number of
animals occur near Bree-Bocholt close to Dutch
border and near the Dutch population (Schockert
2012).
8. Is the organism known to be invasive (i.e. to
threaten organisms, habitats or ecosystems)
anywhere in the world?
Yes The most evident damage caused by Pallas’s
squirrels is bark stripping, especially where and
when food availability is weak (Guo et al. 2011): it
can be really important as reported in France
(Jouanin 1986), Argentina (Guichón & Doncaster,
2008) and Japan (Tamura & Ohara 2005). Bark
stripping increases the risk of fungal infections and
invertebrate damage, which can reduce timber
yield (Mayle 2010). Another impact of C.
erythraeus may be linked to the use of leaves,
branches and bark to build its nests.
Some potential problems of predation on native
fauna have been mentioned in Argentina and Japan
where predation on eggs was observed (Pereira et
al. 2003; Guichón et al. 2005, 2009; Azuma 1998)
but further studies are required. Unpublished data
from North Italy suggest that interspecific
competition with the native red squirrel occurs
EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
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resulting in reduced density or even disappearance
of the native species (Mazzamuto unpubl. data)
9. Describe any known socio-economic benefits of
the organism in the risk assessment area.
None known
Stage 2. Screening Questions
10. Has this risk assessment been requested by the
Programme Board? (If uncertain check with the
Non-native Species Secretariat)
NA
11. What is the reason for performing the risk
assessment?
Identification of invasive alien species of EU
concern
12. Does the organism have intrinsic attributes that
indicate that it could be invasive, i.e. threaten
species, habitats or ecosystems?
Tree squirrels are highly adaptive and
opportunistic species and viable populations could
establish from few founders. The likelihood ratio
for a couple of Callosciurus spp. (C. erythraeus and C. finlaysonii the introduced species considered) to
successfully establish a viable population is 73%
and a likelihood ratio of 90% is achieved with >4
animals (Bertolino 2009). The number of yearly litters is from 1 to 3 if the
mast production (food supply) is high, with an
average of 1.4 weaned offspring (Tamura et al.
1989; Dijkstra, com. pers.).
Few studies of dispersal distances are available for
this squirrel species, but it is usually considered
that the maximum dispersal distance is about 5 km
(Lin & Yo 1981, Guichón & Doncaster 2008).
The species lives in deciduous, mixed and
coniferous woodland habitats (Chapuis et al. 2011,
Dijkstra & Dekker 2008, Dijkstra et al. 2009)
feeding on tree seeds and a variety of other foods
(tree flowers, buds, mushrooms, berries,
occasionally insects and bird eggs; they may
sometimes feed on cereals). The species is also
EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
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found in suburban areas where it benefits from
supplemental feeding (Bertolino & Lurz 2013).
13. Does the organism occur outside effective
containment in Europe?
Yes
14. Is the organism widely distributed in Europe?
Yes Pallas’s squirrel populations are present in France
(Chapuis & Menigaux 2010), The Netherlands
(Dijkstra 2010), Italy (Martinoli et al. 2010), and
Belgium (Schockert 2012).
15. Does at least one species (for herbivores,
predators and parasites) or suitable habitat vital for
the survival, development and multiplication of the
organism occur in Europe, in the open, in
protected conditions or both?
Yes The species is found in deciduous and mixed forest
and in urban parks (open); it is also present in
zoological gardens and as a pet in private houses
and parks (protected conditions).
16. Does the organism require another species for
critical stages in its life cycle such as growth (e.g.
Yes The species is present in zoological gardens and
private collections.
20. Has the organism entered and established
viable (reproducing) populations in new areas
outside its original range, either as a direct or
indirect result of man’s activities?
Yes The species has been introduced to many localities
of Japan (from years 1930s), Argentina (from
1970) and Hong Kong (1972) establishing viable
populations. In Europe, Pallas’s squirrel was
introduced in Southern France at the end of the
1960s, while in The Netherlands (3 populations),
Italy (1 population) and Belgium (two populations,
one eradicated ) the populations reported are quite
recent (from 1998 onwards) (Bertolino & Lurz
2013).
21. Can the organism spread rapidly by natural
means or by human assistance?
Yes Good natural dispersal capacity (Lin & Yo 1981;
Guichón & Doncaster 2008). Humans can further
promote the spread of the species with
translocation from one area to another (Shorten
1954; Guichón et al. 2005; Martinoli et al. 2010).
22. Could the organism as such, or acting as a
vector, cause economic, environmental or social
harm in Europe?
Yes In its native area C. erythraeus is considered as a
tropical crop pest (Hill 2008). It causes damages in
fruit trees and crop plantations, eating and spoiling
the fruits which are eaten as well as the green parts
of coveted plants and significant economic impacts
in the native range have been pointed out in many
publications (especially on conifer plantations; Lin
& Yo 1981; Kuo 1982; Tsui et al. 1982).
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In the new recipient areas, the most evident
damage caused by this species is also bark
stripping (especially where and when food
availability is weak, Guo et al. 2011) with
substantial economic loss of profit in tree
plantations (Jouanin 1992, Stuyck et al. 2009);
damage can be really important as reported in
France (Chapuis & Menigaux 2010), Argentina
(Guichón et al. 2009) and Japan (Tamura & Ohara
2005). In Argentina the consumption of cereals in
storage silos is also reported (Guichón et al. 2009,
Bertolino & Lurz 2013). However most of the data
are qualitative and don't enable us to assess the
quantitative losses caused by the Pallas's squirrel
(Bertolino & Lurz 2013). Another impact of C.
erythraeus may be linked to the use of leaves,
branches and bark to build its nests.
The species is also considered as a pest because of
damages caused in gardens and plantations (bark
stripping of trees and shrubs, fruit consumption
especially in olive and citrus plantations and in
orchards) and damages to infrastructures like
telephonic cables, sprinkler systems, etc. In
Argentina, such problems of deterioration of
lighting, television and telephonic cables have also
been reported (Dijkstra et al. 2009; Guichón et al.
2005, 2009; Chapuis & Menigaux 2010). Thus,
nowadays, in France part of the citizens call it
"Korean rat" (Chapuis et al. 2011).
Competition with native species like the red
squirrel (Sciurus vulgaris) is also considered a
strong potential impact (Chapuis et al. 2011;
Mazzamuto unpub. data) and transmission of
pathogens could likely cause a risk but, currently,
it is not documented enough.
EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
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SECTION B – Detailed assessment
PROBABILITY OF ENTRY
Important instructions:
Entry is the introduction of an organism into Europe. Not to be confused with spread, the movement of an organism within Europe.
For organisms which are already present in Europe, only complete the entry section for current active pathways of entry or if relevant potential future
pathways. The entry section need not be completed for organisms which have entered in the past and have no current pathways of entry.
QUESTION RESPONSE [chose one entry,
delete all others]
CONFIDENCE [chose one entry,
delete all others]
COMMENT
1.1. How many active pathways are relevant to the
potential entry of this organism?
(If there are no active pathways or potential future
pathways respond N/A and move to the Establishment
section)
few
very high The species is already present in the Risk Assessment
area with viable and spreading populations in four
countries.
The pathway for new introduction is escapes from pet
owners, deliberate release from pet owners, deliberate
introductions.
1.2. List relevant pathways through which the organism
could enter. Where possible give detail about the specific
origins and end points of the pathways.
For each pathway answer questions 1.3 to 1.10 (copy and
paste additional rows at the end of this section as
necessary).
[Pet-trade] The primary pathway for entry involves their escape or
deliberate release from captivity. The origin of the
pathway is considered to be the keeping of the animals
in captivity but also deliberate introductions in parks
and woods. Likelihood of association is considered to
remain high as long as the species continues to be kept
in captivity and sold by pet shops (Bertolino 2009).
Natural populations could be the source of animals for
an illegal trade of the species (Signorile et al. 2014b).
Pathway name:
[Pet-trade]
1.3. Is entry along this pathway intentional (e.g. the
organism is imported for trade) or accidental (the
organism is a contaminant of imported goods)?
intentional
very high The species is intentionally imported and traded in
many European countries (UNEP-WCMC 2010). The
animals may then be released or escape.
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(If intentional, only answer questions 1.4, 1.9, 1.10, 1.11)
1.4. How likely is it that large numbers of the organism
will travel along this pathway from the point(s) of origin
over the course of one year?
Subnote: In your comment discuss how likely the
organism is to get onto the pathway in the first place.
moderately likely
medium
Trade statistics are not available. An internet survey
conducted in November 2010, in order to investigate
whether the species appears to be traded within the EU,
and whether there appears to be demand for this species
as a pet, found adverts for the sale of Pallas’s squirrels
on Danish and Swedish websites; there were several
advertisements for people wanting ‘squirrels’ in
German and Swedish websites (UNEP-WCMC 2010).
1.9. How likely is the organism to be able to transfer from
the pathway to a suitable habitat or host?
very likely high
Natural populations can establish from few founders
and grow quickly (Shorten 1954; Bertolino 2009; Wood
et al. 2007). The species is often released in urban
parks, suburban gardens, parkland, etc., which could
provide suitable habitats with supplemental feeding
from humans (Bertolino et al. 2004; Bonnington et al.
2014a,b), and from here spread to forested habitats
(deciduous, mixed and coniferous woodland)
(Miyamoto et al. 2004; Guichón et al. 2005).
1.10. Estimate the overall likelihood of entry into Europe
based on this pathway?
likely
high
The species is already present in Italy, France, Belgium
and The Netherlands and is traded in many others.
End of pathway assessment, repeat as necessary.
1.11. Estimate the overall likelihood of entry into Europe
based on all pathways (comment on the key issues that
lead to this conclusion).
likely
high
The principal pathway for entry is escape or release
from captivity. The origin of the pathway is considered
to be the keeping of the animals in captivity but also
deliberate introductions in parks and woods. Likelihood
of association is considered to remain high as long as
the species continues to be kept in captivity and sold by
pet shops (Bertolino 2009). Natural populations could
be the source of animals for an illegal trade of the
species (Signorile et al. 2014b).
In Italy a Decree signed on 24th December 2013 forbids
trading, raising and keeping of Pallas’s squirrel and two
EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
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other squirrel species (Sciurus niger, Sciurus
carolinensis). In The Netherlands there is the
prohibition of trading and keeping the same three
species since July 2012. In Belgium with the Royal
Decree of 16th July 2009 C. erythraeus has not been
included in the short positive list of mammal species
that may be held by private people. This, however, does
not stop the movements of animals within Europe
where the species is already sold in some countries
(UNEP-WCMC 2010).
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PROBABILITY OF ESTABLISHMENT
Important instructions:
For organisms which are already well established in Europe, only complete questions 1.15 and 1.21 then move onto the spread section. If uncertain,
check with the Non-native Species Secretariat.
QUESTION RESPONSE CONFIDENCE COMMENT
1.12. How likely is it that the organism will be able to
establish in Europe based on the similarity between
climatic conditions in Europe and the organism’s current
distribution?
very likely very high The species already established in France,
Belgium, The Netherlands and Italy (Bertolino &
Lurz 2013).
If they initially originate from tropical and
subtropical climate, due to their flexibility, they
are also able to colonize warm temperate
environments (Chapuis et al. 2011; Bertolino &
Lurz 2013). Dutch cold climate also fully matches
with the species requirements (Dijkstra & Dekker
2008).
For these reasons climatic conditions in most of
Europe is considered suitable for Pallas’s squirrels.
1.13. How likely is it that the organism will be able to
establish in Europe based on the similarity between other
abiotic conditions in Europe and the organism’s current
distribution?
very likely very high The species lives in deciduous, mixed and
coniferous woodland habitats so all the temperate
forests and woodlands in Europe have many tree
species that provide food resources to the species;
(sub)urban park populations occur both in Europe
and in the native Asian range.
1.14. How likely is it that the organism will become
established in protected conditions (in which the
environment is artificially maintained, such as wildlife
Subnote: gardens are not considered protected conditions
very likely very high The species is already keeps in wildlife parks,
zoological gardens, private collections and pet
shops.
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1.15. How widespread are habitats or species necessary
for the survival, development and multiplication of the
organism in Europe?
widespread very high The species lives in deciduous, mixed and
coniferous woodland habitats, feeding on nuts,
seeds, tree flowers, buds, mushrooms, berries,
caterpillars, rarely on insects and bird eggs and
sometimes on cereals. The species is also found in
parks and towns. Therefore no single species is
“vital” for its survival, development and
multiplication. Suitable habitats are present and
widely distributed in the Risk Assessment Area.
1.16. If the organism requires another species for critical
stages in its life cycle then how likely is the organism to
become associated with such species in Europe?
NA
1.17. How likely is it that establishment will occur despite
competition from existing species in Europe?
likely
high
There are some data indicating competition with
the native red squirrel, but outcome seems in
favour of the alien species (Chapuis et al. 2001;
Mazzamuto unpub. data)
1.18. How likely is it that establishment will occur despite
predators, parasites or pathogens already present in
Europe?
very likely high
A range of potential predators exist in Europe,
these include raptors, red fox (Vulpes vulpes),
stone and pine marten (Martes spp.), feral and
domestic cats, and potentially owls. This suite of
predators has not prevented the establishment, nor
the spread of the animals were the species has
been introduced in Europe.
1.19. How likely is the organism to establish despite
existing management practices in Europe?
likely high
In Belgium the species is not included in the short
positive list of mammal species that may be held
by private people and in The Netherlands and Italy
there is the prohibition of trading and keeping the
species. However, the species is still sold in other
countries so a general wildlife management
strategy in continental Europe is absolutely needed
because all countries don’t invest the same energy
to prevent introductions of exotic species on their
territory (Genovesi & Shine 2004). Just one
population in Belgium has been eradicated while
EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
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in The Netherlands, France and Italy eradication is
still in progress. These management actions would
stop the spread of established populations, but not
the risk for Europe. The main pathway of entry is
the pet trade and the risk of new introductions in
other European countries continues to be present. 1.20. How likely are management practices in Europe to
facilitate establishment?
NA
1.21. How likely is it that biological properties of the
organism would allow it to survive eradication campaigns
in Europe?
moderately likely
medium
The dispersal potential of the species seems to be
very limited, but it is also clear that established
populations in Europe and South America
originated from few animals (Wood et al. 2007,
Bertolino 2009), thus proving the adaptability of
Callosciurus erythraeus to new habitats, even if
the colonization is slow and thus moderate
(Dijkstra et al. 2009). Tree squirrels are generally
considered as particularly adaptable because of
their relatively high reproductive potential, wide
food habits, and plasticity to anthropogenic
habitats (Palmer et al. 2007, UNEP-WCMC 2010).
Thus, prompt actions are recommended in any
case of suspected invasiveness leading to possible
impacts (Stuyck et al. 2009; Schockert 2012).
1.22. How likely are the biological characteristics of the
organism to facilitate its establishment?
very likely high
The number of yearly litters is from 1 to 3 if the
mast production (food supply) is high, with an
average of 1.4 weaned offspring (Tamura et al.
1989; Dijkstra, com. pers.). The species has wide
food habits and adaptability to new habitats
(Bertolino & Lurz 2013).
1.23. How likely is the capacity to spread of the organism
to facilitate its establishment?
likely
high
The dispersal capacity of juveniles away from
their natal home range is considered to be lower
than 5 km/year (Lin & Yo 1981, Guichón &
Doncaster 2008). Bridgeman et al. (2012) consider
C. erythraeus as able to cross some habitat gaps if
EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
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the distance without connectivity is smaller than
100 m.
1.24. How likely is the adaptability of the organism to
facilitate its establishment?
very likely very high The species could adapt to urban, suburban and
more natural area, occurring in a variety of
woodland habitat types
1.25. How likely is it that the organism could establish
despite low genetic diversity in the founder population?
likely
high Pallas’s squirrels have proven to be very
successful invaders able to start new populations
and spread even from few founders (Bertolino
2009; Schockert 2012).
1.26. Based on the history of invasion by this organism
elsewhere in the world, how likely is to establish in
Europe? (If possible, specify the instances in the
comments box.)
very likely very high 25 out of 29 (86.2%) introductions outside the
native range in Asia, South America, Europe were
successful (Bertolino & Lurz 2013). The species
already established in North (Belgium, The
Netherlands) and South (France, Italy) Europe,
showing its ability to adapt to European habitats.
1.27. If the organism does not establish, then how likely is
it that transient populations will continue to occur?
Subnote: Red-eared Terrapin, a species which cannot re-
produce in EU but is established because of continual
release, is an example of a transient species.
unlikely
medium
If the species does not establish is probable that
the introduced animals will disappear. However,
the risk of new introductions will continue to
remain.
1.28. Estimate the overall likelihood of establishment
(mention any key issues in the comment box).
likely
high The species already established in North (Belgium,
The Netherlands) and South (France, Italy)
Europe. Climatic conditions in most of Europe are
considered suitable for Pallas’s squirrels (Chapuis
et al. 2011; Bertolino & Lurz 2013; Dijkstra &
Dekker 2008). If they initially originate from
tropical and subtropical broadleaf forests, they
were also able to colonize warm temperate
environments (Setoguchi 1990, Sheng et al. 1999)
as well as subalpine broadleaf and coniferous
forests until 3000 m of altitude (Smith & Xie
2008) indicating a certain adaptability of the
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species. The species could adapt to urban,
suburban and more natural area, occurring in a
variety of woodland habitat types. Callosciurus
erythraeus proven to be a very successful invader
able to start new populations world-wide even
from few founders (Bertolino 2009; Schockert
2012). Humans could help the spreading
translocating them to new areas.
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PROBABILITY OF SPREAD
Important notes:
Spread is defined as the expansion of the geographical distribution of a pest within an area.
QUESTION
RESPONSE CONFIDENCE COMMENT
2.1. How important is the expected spread of this
organism in Europe by natural means? (Please list and
comment on the mechanisms for natural spread.)
major
high
Active saturation dispersal, mainly of immature
individuals, which will colonize new areas of suitable
habitat. Quantitative studies are not reported for
Europe but the mean areal expansion rate observed in
Japan and Argentina varies between 6 and 22
km²/year and is known to increase after the
establishment phase.
2.2. How important is the expected spread of this
organism in Europe by human assistance? (Please list and
comment on the mechanisms for human-assisted spread.)
major
high
Human assistance may amplify the potential of
expansion of C. erythraeus by translocation.
The main pathway of Pallas’s Introductions in Europe
has been connected to private citizens and animal
traders who keep animals in captivity, with
consequent risk of escape or release them into public
estates and parks (Schockert 2012).
2.3. Within Europe, how difficult would it be to contain
the organism?
difficult
medium
Likelihood is that it could be 'contained' where it
doesn't spread over large areas, partly because of
seasonally high trappability, and partly because of
easy recognition of the species in new areas.
However, practical difficulties likely to arise because
of diverse landownership patterns likely to be
encountered in typical release/escape areas and
because of potential public opposition to
control/eradication (Barr et al. 2002; Rushton et al.
2002).
2.4. Based on the answers to questions on the potential for [Most of Europe] high See answers to questions 4 and 5 of EU CHAPPEAU
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establishment and spread in Europe, define the area
endangered by the organism.
2.5. What proportion (%) of the area/habitat suitable for
establishment (i.e. those parts of Europe were the species
could establish), if any, has already been colonised by the
organism?
0-10
high
2.6. What proportion (%) of the area/habitat suitable for
establishment, if any, do you expect to have been invaded
by the organism five years from now (including any
current presence)?
0-10
medium
Eradication programs are ongoing for all the colonies
present in Italy, France, Belgium and Netherlands. If
these management actions will not be effective a
limited expansion is expected in next years.
2.7. What other timeframe (in years) would be appropriate
to estimate any significant further spread of the organism
in Europe? (Please comment on why this timeframe is
chosen.)
10
high
In 10 years the outcome of the eradication programs
ongoing in the four countries will be clear
2.8. In this timeframe what proportion (%) of the
endangered area/habitat (including any currently occupied
areas/habitats) is likely to have been invaded by this
organism?
0-10
medium
Depending on the results of the eradication programs
2.9. Estimate the overall potential for future spread for
this organism in Europe (using the comment box to
indicate any key issues).
moderately
medium
Few studies of dispersal distances are available for
this squirrel species, but it is usually considered that
the maximum dispersal distance is about 5 km (Lin &
Yo 1981, Guichón & Doncaster 2008).
In case of new introduction in other countries, the
likelihood of establishment is high and the spread
could be from slowly to moderate, depending on the
habitat.
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PROBABILITY OF IMPACT
Important instructions:
When assessing potential future impacts, climate change should not be taken into account. This is done in later questions at the end of the assessment.
Where one type of impact may affect another (e.g. disease may also cause economic impact) the assessor should try to separate the effects (e.g. in this
case note the economic impact of disease in the response and comments of the disease question, but do not include them in the economic section).
Note questions 2.10-2.14 relate to economic impact and 2.15-2.21 to environmental impact. Each set of questions starts with the impact elsewhere in
the world, then considers impacts in EUROPE separating known impacts to date (i.e. past and current impacts) from potential future impacts. Key
words are in bold for emphasis.
QUESTION
RESPONSE CONFIDENCE COMMENTS
2.10. How great is the economic loss caused by the
organism within its existing geographic range excluding
Europe, including the cost of any current management?
major
high
In its native area C. erythraeus is considered as a
tropical crop pest (Hill 2008). It causes damages in fruit
trees and crop plantations, eating and spoiling the fruits
which are eaten as well as the green parts of coveted
plants and significant economic impacts in the native
range have been pointed out in many publications
(especially on conifer plantations; Lin & Yo 1981; Kuo
1982; Tsui et al. 1982).
In the new recipient areas, the most evident damage
caused by this species is also bark stripping (especially
where and when food availability is weak, Guo et al.
2011) with substantial economic loss of profit in tree
plantations; damage can be really important, though not
quantified, as reported Argentina (Guichón et al. 2009)
and Japan (Tamura & Ohara 2005). In Argentina the
consumption of cereals in storage silos is also reported
(Guichón et al. 2009, Bertolino & Lurz 2013).
However most of the data are qualitative and don't
enable us to assess the quantitative losses caused by the
Pallas's squirrel (Bertolino & Lurz 2013).
The species is also considered as a pest because of
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damages caused in gardens and plantations (bark
stripping of trees and shrubs, fruit consumption
especially in olive and citrus plantations and in
orchards) and damages to infrastructures like telephonic
cables, sprinkler systems, etc. In Argentina, such
problems of deterioration of lighting, television and
telephonic cables have also been reported (Guichón et
al. 2005, 2009).
2.11. How great is the economic cost of the organism
currently in Europe excluding management costs (include
any past costs in your response)?
moderate
medium
In Europe the most evident damage caused by this
species is bark stripping, with substantial economic loss
of profit in tree plantations (Jouanin 1992, Stuyck et al.
2009); damage can be really important as reported in
France (Chapuis & Menigaux 2010), though not
quantified. However most of the data are qualitative and
don't enable us to assess the quantitative losses caused
by the Pallas's squirrel (Bertolino & Lurz 2013).
The species is also considered as a pest because of
damages caused in gardens and plantations (bark
stripping of trees and shrubs, fruit consumption
especially in olive and citrus plantations and in
orchards) and damages to infrastructures like telephonic
cables, sprinkler systems, etc. (Dijkstra et al. 2009;
Chapuis & Menigaux 2010).
2.12. How great is the economic cost of the organism
likely to be in the future in Europe excluding management
costs?
moderate
low
If the species is not eradicated or if it establish in other
areas, damage reported in point 2.11 should be probably
moderate, but is some are they could be major. Since
available data are limited there is a high incertitude in
these predictions.
2.13. How great are the economic costs associated with
managing this organism currently in Europe (include any
past costs in your response)?
major
medium
Eradication programs are ongoing in four countries,
manly by means of live trapping and euthanasia or
keeping animals in captivity. Cost evaluation of these
management actions are not yet available, but
considering previous eradication programs on other
species they should be high.
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2.14. How great are the economic costs associated with
managing this organism likely to be in the future in
Europe?
moderate
low
Eradication programs are ongoing and therefore costs
associated will still be present. If the species is not
banned from Europe, the possibility of new
introductions is high and therefore further management
actions will be needed.
2.15. How important is environmental harm caused by the
organism within its existing geographic range excluding
Europe?
major
high
In its native area C. erythraeus is considered as a
tropical crop pest (Hill 2008). It causes damages in fruit
trees and crop plantations, especially in oil palm,
papaya and cocoa trees, eating and spoiling the fruits
which are eaten as well as the green parts of coveted
plants.
In Japan and Argentina the most evident damage
caused by this species is bark stripping (especially
where and when food availability is weak (Guo et al.
2011)) with substantial economic loss of profit in tree
plantations (Tamura & Ohara 2005; Guichón et al.
2009). In Argentina the consumption of cereals in
storage silos, damages to infrastructures like telephonic
and television cables, sprinkler systems have also been
reported (Guichón et al. 2005, 2009).
In Japan the Pallas’s squirrel could have an impact on
the native squirrel species, Sciurus lis, that is locally
declining (Ministry of the Environment, Japan, 2002;
Hori et al. 2006).
2.16. How important is the impact of the organism on
biodiversity (e.g. decline in native species, changes in
native species communities, hybridisation) currently in
Europe (include any past impact in your response)?
major
high
The activity of bark stripping typical of the species
increases the risk of fungal infections and invertebrate
damage with an influence on the flora and fauna
associated with specific woodland types. Another
impact may be linked to the use of leaves, branches and
bark to build its nests.
There are some potential problems of predation on bird
eggs (Pereira et al. 2003; Guichón et al. 2005, 2009;
Azuma 1998) but further studies are required on
whether they contribute to the decline of particular
woodland bird species in Europe.
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Competition with native species like Sciurus vulgaris is
also considered a strong potential impact (Chapuis et
al. 2011; Mazzamuto unpubl. data) and transmission of
pathogens could likely cause a risk but, currently, it is
not documented enough.
2.17. How important is the impact of the organism on
biodiversity likely to be in the future in Europe?
major
high
If uncontrolled, the spread of the Pallas’s squirrel from
Italy to France and Switzerland, and in the long term to
other European countries, or the direct introduction of
the species to other countries, could probably affect the
native red squirrel.
2.18. How important is alteration of ecosystem function
(e.g. habitat change, nutrient cycling, trophic
interactions), including losses to ecosystem services,
caused by the organism currently in Europe (include any
past impact in your response)?
moderate
medium
Bark stripping could influence woodland management
practices, with a shift away from trees susceptible to
squirrel damage (Mayle, 2005), with an influence on the
flora and fauna associated with specific woodland types.
2.19. How important is alteration of ecosystem function
(e.g. habitat change, nutrient cycling, trophic
interactions), including losses to ecosystem services,
caused by the organism likely to be in Europe in the
future?
moderate
low
Bark stripping could influence woodland management
practices (Mayle, 2005); its impact, however, will
depend on the results of the eradication programs. In
case of introductions of the species in other countries
woodland damage and alteration will depends on local
management practices.
2.20. How important is decline in conservation status (e.g.
sites of nature conservation value, WFD classification)
caused by the organism currently in Europe?
moderate
high
Though not included in the Habitat Directive, the
extinction of the red squirrel with its replacement by the
Pallas’s squirrel decreases the conservation status of
many areas.
2.21. How important is decline in conservation status (e.g.
sites of nature conservation value, WFD classification)
caused by the organism likely to be in the future in
Europe?
moderate
high
A decrease in the conservation status of many areas is
expected if the red squirrel will be replaced by the
Pallas’s squirrel in other parts of France, Belgium,
Netherlands and Italy and possibly in new areas of
introduction.
2.22. How important is it that genetic traits of the
organism could be carried to other species, modifying
their genetic nature and making their economic,
NA
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environmental or social effects more serious?
2.23. How important is social, human health or other
harm (not directly included in economic and
environmental categories) caused by the organism within
its existing geographic range?
minimal
low
Not known
2.24. How important is the impact of the organism as
food, a host, a symbiont or a vector for other damaging
organisms (e.g. diseases)?
minimal
low
Transmission of pathogens could likely be a risk but,
currently, it is not documented enough.
2.25. How important might other impacts not already
covered by previous questions be resulting from
introduction of the organism? (specify in the comment
box)
minimal
low
Not known
2.26. How important are the expected impacts of the
organism despite any natural control by other organisms,
such as predators, parasites or pathogens that may already
be present in Europe?
major
medium
Predation is only rarely a cause of mortality in Pallas’s
squirrel populations (Tamura et al. 1989; Chapuis 2011;
Schockert 2012 ). Parasites and pathogens present in
Belgium, France, Netherlands and Italy do not limit the
species (Dozières et al. 2010).
2.27. Indicate any parts of Europe where economic,
environmental and social impacts are particularly likely to
occur (provide as much detail as possible).
Depends on
eradication
outcomes
and/or new
introductions]
medium
Italy, France, Belgium, The Netherlands if eradication
projects will not be effective.
In other countries in the Continental and Mediterranean
biogeographic areas if the species will be introduced.
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RISK SUMMARIES
RESPONSE CONFIDENCE COMMENT
Summarise Entry very likely high
The species is already present in the Risk Assessment
area in Italy, France, Belgium and The Netherlands with
viable populations (Bertolino & Lurz 2013).
The primary pathway for entry involves their escape or
deliberate release from captivity. The origin of the
pathway is considered to be the keeping of the animals
in captivity but also deliberate introductions in parks
and woods. The species is still intentionally imported
and traded in many European countries (UNEP-WCMC
2010) and is already keeps in wildlife parks, zoological
gardens, private collections and pet shops.
Summarise Establishment very likely high
The species already established in France, Belgium,
The Netherlands and Italy (Bertolino & Lurz 2013).
If they initially originate from tropical and subtropical
climate, due to their flexibility, they are also able to
colonize warm temperate environments (Chapuis et al.
2011; Bertolino & Lurz 2013). Dutch cold climate also
fully matches with the species requirements (Dijkstra &
Dekker 2008). For these reasons climatic conditions in
most of Europe is considered suitable for Pallas’s
squirrels.
The species lives in deciduous, mixed and coniferous
woodland habitats so all the temperate forests and
woodlands in Europe have many tree species that
provide food resources to the species; (sub)urban park
populations occur both in Europe and in the native
Asian range.
Summarise Spread moderately
medium
Eradication programs are ongoing for all the colonies
present in Italy, France, Belgium and Netherlands. If
these management actions will not be effective an
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expansion is expected in next years.
In case of new introduction in other countries, the
likelihood of establishment is high and the spread could
be from slowly to moderate, depending on the habitat.
Active saturation dispersal, mainly of immature
individuals, which will colonize new areas of suitable
habitat. Quantitative studies are not reported for Europe
but the mean areal expansion rate observed in Japan and
Argentina varies between 6 and 22 km²/year and is
known to increase after the establishment phase.
Human assistance may amplify the potential of
expansion of C. erythraeus by translocation
Summarise Impact major
medium
The magnitude of present and future impacts will
depends on the results of ongoing management
activities and the possible establishment of new
populations
The most evident damage caused by Pallas’s squirrels is
bark stripping, especially where and when food
availability is weak (Guo et al. 2011): it can be really
important as reported in France (Jouanin 1986),
Argentina (Guichón & Doncaster, 2008) and Japan
(Tamura & Ohara 2005). Bark stripping increases the
risk of fungal infections and invertebrate damage,
which can reduce timber yield (Mayle 2010). Another
impact of C. erythraeus may be linked to the use of
leaves, branches and bark to build its nests.
Some potential problems of predation on native fauna
have been mentioned in Argentina and Japan where
predation on eggs was observed (Pereira et al. 2003;
Guichón et al. 2005, 2009; Azuma 1998) but further
studies are required. Unpublished data from North Italy
suggest that interspecific competition with the native
red squirrel occurs resulting in reduced density or even
disappearance of the native species (Mazzamuto
unpubl. data).
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Conclusion of the risk assessment high medium
A large number of scientific publications demonstrate
the invasiveness of Callosciurus erythraeus in terms of
establishment probabilities and damage to forestry and
plantations. Data on the possible impacts on native
species (e.g. predation or competition) are scanty
though preliminary results of ongoing research suggest
that interspecific competition with the native red
squirrel occurs resulting in reduced density or even
disappearance of the native species (Mazzamuto
unpubl. data).
Additional questions are on the following page ...
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ADDITIONAL QUESTIONS - CLIMATE CHANGE 3.1. What aspects of climate change, if any, are most
likely to affect the risk assessment for this organism?
[climate
directly]
high
Callosciurus erythraues initially originate from tropical
and subtropical broadleaf forests, due to their
flexibility, they were also able to colonize warm
temperate environments (Setoguchi 1990; Sheng et al.
1999) as well as subalpine broadleaf and coniferous
forests until 3000 m of altitude (Smith & Xie 2008), but
it seems they were not able to colonize the northern
deciduous forests with harsh winter conditions (i.e.
large snow precipitations and a mean temperature of
coldest months lower than -4°C) (Setoguchi 1990,
Bertolino 2009). Frost sensitivity of the Pallas’s squirrel
is likely to reduce its establishment capacity but the
Dutch climate fully matches with the species
requirements (Dijkstra & Dekker 2008).
Considering that warmer and drier conditions seem to
favour the spread of the species, the present climate
change may further benefit the species in colonising
new areas.
3.2. What is the likely timeframe for such changes?
50 - 100 years medium
3.3. What aspects of the risk assessment are most likely to
change as a result of climate change?
[Increase
suitability of
some habitats]
medium
ADDITIONAL QUESTIONS - RESEARCH 4.1. If there is any research that would significantly
strengthen confidence in the risk assessment please
summarise this here.
[The impact to
native fauna
should be
further
investigated]
medium
Confidence in the risk assessment is high for
establishment, spread and damage to forestry and
plantations. Data on the possible impacts on native
species are scanty though preliminary results suggest a
possible competition with the native red squirrel; there
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are also occasional reports of bird eggs predation. The
impacts on native species should be further investigated
to better evaluate the level of invasiveness of the
species.
The outcomes of the ongoing eradication programs
should be published to better evaluate costs and
effectiveness of these management actions.
Please provide a reference list on the following page ...
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de la Société Française pour l'Étude et la Protection des Mammifères, Saint Jean du Bray : 277-283.
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Foundation 65: 9-11.
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EUROPEAN NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE V1.3 (09-11-11)
32
Miyamoto A., Tamura N., Sugimura K., Yamada F. (2004). Predicting habitat distribution of the alien Formosan squirrel using logistic regression model. Global
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RISK ASSESSMENT COVERING PAGE - ABOUT THE PROCESS It is important that policy decisions and action within Europe are underpinned by evidence. At the same time it is not always possible to have complete scientific
certainty before taking action. To determine the evidence base and manage uncertainty a process of risk analysis is used.
Risk analysis comprises three component parts: risk assessment (determining the severity and likelihood of a hazard occurring); risk management (the practicalities of
reducing the risk); and risk communication (interpreting the results of the analysis and explaining them clearly). This tool relates to risk assessment only. The Non-native
Species Secretariat manages the risk analysis process on behalf of the GB Programme Board for Non-native Species. During this process risk assessments are:
Commissioned using a consistent template to ensure the full range of issues is addressed and maintain comparable quality of risk and confidence scoring supported
by appropriate evidence.
Drafted by an independent expert in the species and peer reviewed by a different expert.
Approved by the NNRAP (an independent risk analysis panel) only when they are satisfied the assessment is fit-for-purpose.
Approved by the GB Programme Board for Non-native Species.
Placed on the GB Non-native Species Secretariat (NNSS) website for a three month period of public comment.
Finalised by the risk assessor to the satisfaction of the NNRAP and GB Programme Board if necessary.
Common misconceptions about risk assessments
The risk assessments:
Consider only the risks (i.e. the chance and severity of a hazard occurring) posed by a species. They do not consider the practicalities, impacts or other issues
relating to the management of the species. They also only consider only the negative impacts of the species, they do not consider any positive effects. They
therefore cannot on their own be used to determine what, if any, management response should be undertaken.
Are advisory and therefore part of the suite of information on which policy decisions are based.
Are not final and absolute. They are an assessment based on the evidence available at that time. Substantive new scientific evidence may prompt a re-evaluation of
the risks and/or a change of policy.
Period for comment
Once placed on the NNSS website, risk assessments are open for stakeholders to provide comment on the scientific evidence which underpins them for three months.
Relevant comments are collated by the NNSS and sent to the risk assessor for them to consider and, if necessary, amend the risk assessment. Where significant comments are
received the NNRAP will determine whether the final risk assessment suitably takes into account the comments provided.
To find out more: published risk assessments and more information can be found at https://secure.fera.defra.gov.uk/nonnativespecies/index.cfm?sectionid=22
Entry is the introduction of an organism into Europe. Not to be confused with spread, the movement of an organism within Europe.
For organisms which are already present in Europe, only complete the entry section for current active pathways of entry or if relevant potential future
pathways. The entry section need not be completed for organisms which have entered in the past and have no current pathways of entry.
QUESTION RESPONSE [chose one entry,
delete all others]
CONFIDENCE [chose one entry,
delete all others]
COMMENT
1.1. How many active pathways are relevant to the
potential entry of this organism?
(If there are no active pathways or potential future
pathways respond N/A and move to the Establishment
section)
none
high
The coypu is not traded and is not farmed anymore;
therefore, there are no active pathways or potential
future pathways. Natural spread from areas where the
species is already established poses the most significant
risk of expansion.
1.2. List relevant pathways through which the organism
could enter. Where possible give detail about the specific
origins and end points of the pathways.
For each pathway answer questions 1.3 to 1.10 (copy and
paste additional rows at the end of this section as
necessary).
[insert text]
Pathway name:
[inset pathway name here]
1.3. Is entry along this pathway intentional (e.g. the
organism is imported for trade) or accidental (the
When assessing potential future impacts, climate change should not be taken into account. This is done in later questions at the end of the
assessment.
Where one type of impact may affect another (e.g. disease may also cause economic impact) the assessor should try to separate the effects (e.g. in this
case note the economic impact of disease in the response and comments of the disease question, but do not include them in the economic section).
Note questions 2.10-2.14 relate to economic impact and 2.15-2.21 to environmental impact. Each set of questions starts with the impact elsewhere in
the world, then considers impacts in Europe separating known impacts to date (i.e. past and current impacts) from potential future impacts. Key
words are in bold for emphasis.
QUESTION
RESPONSE CONFIDENCE COMMENTS
2.10. How great is the economic loss caused by the
organism within its existing geographic range excluding
Europe, including the cost of any current management?
massive medium
In Italy, during a six-year period (1995-2000) with a
management cost of € 2,614,408, the damage produced
by the species amounted to € 11,631,721 (Panzacchi et
al. 2007). Kettunen et al. (2009) considering the whole
current European range extrapolated a cost of 65.69
million €/year.
Economic loss are associated to damage to agriculture,
river banks and control costs. The most important
economic damage is caused by coypu’s burrowing
behaviour. Coypus dig extensive burrow systems into
the riverbanks and ditches. In Italy, the cost of
riverbank repair following damage by coypus, was
estimated at nearly 2 million Euros/year (Panzacchi et
al. 2007).
2.11. How great is the economic cost of the organism
currently in Europe excluding management costs (include
any past costs in your response)?
massive medium
In Italy, during a six-year period (1995-2000) the
damage produced by the species amounted to €
11,631,721 (Panzacchi et al. 2007). Kettunen et al.
(2009) considering the whole current European range
extrapolated a cost of 65.69 million €/year without a
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Netherlands, p 364.
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inland waters: Profiles, distribution, and threats, Springer, pp 175-191.
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Journal of Mammalogy 22: 333-339.
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928-930.
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Wildlife Society Bulletin 30: 162-175.
Carter J., Foote A.L., Johnson-Randall L. A. 1999. Modelling the effects of coypu (Myocastor coypus) on wetland loss. Wetlands 19: 209-219.
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Naturalists Society 20: 32-35.
Foote A.L., Johnson L.A. 1993. Plant stand development in Louisiana coastal wetlands: coypu grazing effects on plant biomass. in Proceedings of the 13th
Annual Conference of the Society of Wetland Scientists, New Orleans, Louisiana, Society of Wetland Scientists, Utica, Mississippi, USA, pp. 265-271
Gosling L.M. 1981. Climatic determinants of spring littering by feral coypus (Myocastor coypus). Journal of Zoology 195: 281-288.
Gosling L.M., Baker S.J. 1989. The eradication of muskrats and coypus from Britain. Biological Journal of the Linnean Society 38: 39-51
Gosling L.M., Baker S.J. 2008. Coypu Myocasto coypus. In S. Harris, D. W. Yalden (eds), Mammals of the British Isles: Handbook, 4th edn, The Mammal
Society, Southampton, pp 159-165
Guichón M.L., Doncaster C.P., Cassini M.H. 2003. Population structure of coypus (Myocastor coypus) in their region of origin and comparison with
introduced populations. Journal of Zoology 261: 265-272.
Howerth E.W., Reeves A.J., McElveen M.R., Austin F.W. 1994. Survey of selected diseases in nutria (Myocastor coypus) from Louisiana. Journal of Wildlife
Diseases 30: 450-453.
Johnson L.A., Foote A.L. 1997. Vertebrate herbivory in managed coastal wetlands: a manipulative experiment. Aquatic Botany 59: 17-32.
Kettunen M., Genovesi P., Gollasch S., Pagad S., Starfinger U. ten Brink P., Shine C. 2008. Technical support to EUstrategy on invasive species (IAS) -
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(IEEP), Brussels, Belgium. 44 pp. + Annexes.
Kim P. 1980. The coypu (Myocastor coypus) in the Netherlands: reproduction, home range and manner of seeking food. Lutra 23: 55-64.
Linscombe G., Kinler N., Wright V. 1981. Nutria population density and vegetative changes in brackish marsh in coastal Louisiana. in J. A. Chapman and D.
Pursley (eds) Proceedings of the Worldwide Furbearer Conference, pp 129-14\.
Llewellyn D.W., Shaffer G.P. 1993. Marsh restoration in the presence of intense herbivory: The role of Justicia lanceolata (Chapm) small. Wetlands 13: 176-
184.
Louisiana Department of Wildlife and Fisheries 2007. Nutria. http://www.nutria.com, accessed 25August 2010.
Marini F, Ceccobelli S, Battisti C 2011. Coypu (Myocastor coypus) in a Mediterranean remnant wetland: a pilot study of a yearly cycle with management
implications. Wetlands Ecology and Management 19: 159-164.
Marini F., Gabrielli E., Montaudo L., Vecchi M., Santoro R., Battisti C., Carpaneto G.M. 2013. Diet of coypu (Myocastor coypus) in a Mediterranean coastal
wetland: a possible impact on threatened rushbeds? Vie Milieu 63: 97-103.
Michel V., Ruveon-Clouet N., Menard A., Sonrier C., Fillonneau C., Rakotovao F., Ganière J.P., André-Fontaine G. 2001. Role of the coypu (Myocastor
coypus. in the epidemiology of leptospirosis in domestic animals and humans in France. European Journal of Epidemiology 17: 111-121.
Nardoni S., Angelici M.C., Mugnaini L., Mancianti F. 2011. Prevalence of Toxoplasma gondiiinfection in Myocastor coypus in a protected Italian wetland.
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Myocastor coypus in Italy versus eradication in East Anglia (UK). Wildlife Biology 13: 159-171.
Prigioni C., Balestrieri A., Remonti L. 2005. Food habits of the coypu Myocastor coypus, and its impact on aquatic vegetation in a freshwater habitat of NW
Italy. Folia Zoologica 54: 269-277.
Purvis A. 2001. Mammalian life histories and responses of populations to exploitation. In J.D. Reynolds, G.M. Mace, K.H. Redford, J.G. Robinson (eds.),
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Entry is the introduction of an organism into Europe. Not to be confused with spread, the movement of an organism within Europe.
For organisms which are already present in Europe, only complete the entry section for current active pathways of entry or if relevant potential future
pathways. The entry section need not be completed for organisms which have entered in the past and have no current pathways of entry.
QUESTION RESPONSE
[chose one entry,
delete all others]
CONFIDENCE
[chose one
entry, delete all
others]
COMMENT
1.1. How many active pathways are relevant to the
potential entry of this organism?
(If there are no active pathways or potential future
pathways respond N/A and move to the Establishment
section)
few
very high The species is already present in the Risk Assessment
area with viable and spreading populations in three
countries.
The pathway for new introduction is escapes from pet
owners, deliberate release from pet owners, deliberate
introductions.
1.2. List relevant pathways through which the organism
could enter. Where possible give detail about the specific
origins and end points of the pathways.
For each pathway answer questions 1.3 to 1.10 (copy and
paste additional rows at the end of this section as
necessary).
[Pet-trade] The primary pathway for entry involves their escape or
deliberate release from captivity (see as an example of
squirrel’s pathway the video on YouTube regarding an
illegal release of a chipmunk, Tamias sp.
(http://www.youtube.com/watch?v=p_Ee4Bvk-eU). The
origin of the pathway is considered to be the keeping of
the animals in captivity but also deliberate introductions
in parks and woods. Likelihood of association is
considered to remain high as long as the species
continues to be kept in captivity and sold by pet shops
(Bertolino 2009). Natural populations could be the
source of animals for an illegal trade of the species
When assessing potential future impacts, climate change should not be taken into account. This is done in later questions at the end of the assessment.
Where one type of impact may affect another (e.g. disease may also cause economic impact) the assessor should try to separate the effects (e.g. in this
case note the economic impact of disease in the response and comments of the disease question, but do not include them in the economic section).
Note questions 2.10-2.14 relate to economic impact and 2.15-2.21 to environmental impact. Each set of questions starts with the impact elsewhere in
the world, then considers impacts in GB separating known impacts to date (i.e. past and current impacts) from potential future impacts. Key words are
in bold for emphasis.
QUESTION
RESPONSE CONFIDENCE COMMENTS
2.10. How great is the economic loss caused by the
organism within its existing geographic range, including
the cost of any current management?
major
high
Total costs for grey squirrel management in UK forests
(damage + control) is estimated at GBP 6,097,320
(Williams et al. 2010) - GBP 10 million (Anon. 2006;
Mayle & Broome 2013) annually. Damage done by
grey squirrels in properties (damage to furniture,
ornaments, cables) is estimated to be GBP 5,128,274;
while the cost of removing squirrels in buildings and
other properties is estimated in GBP 1,914,555 (total
damage + control GBP 7,042,829) (Williams et al.
2010). Projected annual costs of grey squirrel to the
Irish (Ireland and Northern Ireland) agricultural sectors
is GBP 3,635,570 (€ 4,580,818) (Kelly et al. 2013). In
Italy limited damage to maize crops and poplar
plantations are recorded (Currado 1998; Signorile and
Evans 2007).
In Italy two LIFE projects for the control of grey
squirrels in north (2010-2015) and central Italy (2014-
2018) cost: € 1,930,00 and € 1,433,241 respectively.
2.11. How great is the economic cost of the organism
currently in Europe excluding management costs (include
any past costs in your response)?
NA Grey squirrels damage to the timber industry through
bark stripping in Great Britain is estimated at GBP
European projections of grey squirrel’s climatic niche calculated in Maxent using records from native and invasive range (Great Britain, Ireland, Italy). Maps
taken from the results presented in Di Febbraro et al. (2013).